1. Field of the Invention
The present invention relates to couplings for waste water outlets of recreational vehicles and, more particularly, to a coupling for attaching a waste water discharge hose to either of two different types of conventional outlets.
2. Description of Related Art
Recreational vehicles generally include an outside accessible outlet for discharging waste water. A conventional three-inch diameter discharge hose is connected to the outlet through a fitting that is locked onto the outlet. The waste water outlet may be one of two types of conventional configurations. The first type includes two pairs of diametrically opposed dogs formed by cylindrical pegs extending radially outwardly. To engage such an outlet, the fitting, to which the discharge hose is attached, includes a single pair of diametrically opposed hook protrusions for engaging a pair of the two pairs of diametrically opposed dogs. A second type of outlet is similar except that the dogs are essentially rectangular in cross-section having the longitudinal axis extending normal to a radial and in a plane defined by a lateral cross-section of the outlet. The fitting connected to the discharge hose for the second type of outlet includes a pair of diametrically opposed hooks for lockingly engaging a pair of the two pairs of diametrically opposed dogs; the configuration of the hooks corresponds with the lateral cross-section of the dogs to obtain a locking engagement. The fitting for the first type of outlet and its pair of dogs will not lockingly engage the second type of outlet and its pair of dogs and vice versa. Accordingly, the owner of a recreational vehicle must obtain a fitting for the discharge hose which is commensurate with the first or second type of outlet employed on the recreational vehicle.